It is known that ice crystal growth inhibiting agents called "thermal hysteresis proteins" have the capacity to bind to ice crystals and to reduce their growth (Biophysical Journal, February 1991, p 409-418). Two properties of these agents have been demonstrated: they have the capacity to reduce the apparent freezing temperature of a solution without affecting its thawing temperature and they also have the capacity to inhibit the recrystallization of ice crystals (Cryobiology, vol. 25, 1988, p 55-60).
Furthermore, three types of ice crystal growth inhibiting agents have been demonstrated in certain Arctic and Antarctic fish in particular (The FASEB Journal, May 1990, p 2460-2468). These agents are of a protein structure or of a glycoprotein structure. They were isolated from the plasma or the serum of these fish and then purified. However, they are also present in other tissues.
It is also known to use ice crystal growth inhibiting agents to improve the quality of food products such as frozen desserts, frozen pastes or fresh products, such as tomatoes. DNA Plant Technology Corp has synthesized an artificial protein which is an ice crystal growth inhibiting agent similar to those which can be found in certain fish or other organisms capable of living under very low temperature conditions (Food Processing, October 1992, p 55).
However, up until now, no ice crystal growth inhibiting agent has been isolated in Zoarces viviparus, a fish living in particular on the coasts of Norway and on the coasts of the Baltic Sea.